The invention relates to gas analysers and a method of making gas analysers.
A known measuring instrument is a portable gas analyser which measures infrared absorption in a gas cell. The gas cell of the portable gas analyser is a long tube with an infrared source at one end and an infrared detector at the other. Gas is introduced into the tube and is analysed according to the level of absorption of infrared between the source and detector. The known portable gas analyser is relatively long which makes it awkward to transport, carry and use.
There are several problems with the known portable gas analyser. It is not suitable for detecting all gases or concentrations of gas. The gas cell is too short for measuring low concentrations of gas, and too long for measuring high concentrations of gas, where all of the infrared radiation may be absorbed before reaching the detector.